Face-to-face conferences aren't always viable.

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Whenever two or more people gather to share information, collaborate, brainstorm, argue, inform or train one another, that's called a conference.

Conferences can be face-to-face affairs. A salesman attends a trade show to pitch his product to hundreds of potential clients. The accounting department and the CFO sit around a big table and review the fourth-quarter numbers. A consultant flies around the country to train employees on a new software application.

The drawback is that these face-to-face meetings, presentations and training sessions aren't always financially viable. Many of today's companies compete in a global marketplace with offices around the world and clients from Moscow to Moscow (Idaho and Russia, that is).

Communication and technology advances have made it possible to recreate the impact and interactivity of real-world conferences without having to leave your desk.

But what is teleconferencing? How does videoconferencing work? And, what are Web seminars? Read on to find out.